Coffee consumption and risk of hypertension: A prospective analysis in the cohort study.

BACKGROUND: Coffee is one of the most widely consumed beverages around the world. Dietary habits, specifically, coffee consumption has long been a suspected cause of hypertension. However, previous findings on coffee consumption and its association with the incidence of hypertension are not homogeneous and still inconsistent. PURPOSE: To examine the association of habitual coffee consumption with the risk of developing hypertension in a middle-aged Brazilian cohort. METHODS: Data were from the multicenter prospective cohort "Brazilian Longitudinal Study for Adult Health - ELSA-Brasil". The cohort comprises 15,105 civil servants, aged 35-74 years at baseline, who were sampled from universities located in six Brazilian cities. For the present study, we analyzed data from 8780 participants initially free of hypertension during a mean follow-up of 3.9 years. The consumption of coffee was obtained at baseline using a previously validated semi-quantitative food frequency questionnaire (FFQ). Subsequently coffee intake was categorized into four categories (cups/day): never/almost never, ≤1, 1-3, and >3. Hypertension status was defined as a systolic blood pressure ≥140 mmHg or a diastolic blood pressure ≥90 mmHg, use of antihypertensive drug treatment, or both. Poisson regression model with a robust variance was performed to estimate relative risk (RR) and confidence interval (95% CI) for hypertension according to baseline coffee consumption. The effect of interaction between coffee consumption and smoking status was assessed. RESULTS: Most participants (90%) drank coffee, and the median total coffee intake was 150 mL/day. A total of 1285 participants developed hypertension. Compared to participants who never or almost never drink coffee, the risk of hypertension was lower for individuals consuming 1-3 cups/day (RR 0.82, 95% CI: 0.68-0.97) (P for interaction=0.018). After stratification by smoking status the analysis revealed a decreased risk of hypertension in never smokers drinking 1-3 cups of coffee per day (RR 0.79, 95% CI: 0.64-0.98), whereas the hypertension risk among former and current smokers was not associated with coffee consumption significantly. Moreover, upper category of coffee drinking (>3 cups/day) the association was not significant for risk of hypertension. CONCLUSION: The association between coffee consumption and incidence of hypertension was related to smoking status. The beneficial effect of moderate coffee intake (1-3 cups/day) on risk of hypertension was observed only in never smokers.